Method op and apparatus for evaporating liquids



0. CARR.

METHOD OF AND APPARATUS FOR EVA-PORATING LIQUIDS.

APPLICATION FILED FEB. 24. l9l5.

Patented Nov. 11, 1919.

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METHOD OF AND APPARATUS FOR EVAPORATING LIQUIDS. APPLICATION FILED FEB. 24, 1915.

1,321,362. Patented Nov. 11, 1919.

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OMA CARR, OF ASHEVILLE, NORTH CAROLINA.

METHOD OF AND APPARATUS FOR EVAPOBATING LIQUIDS.

Specification of Letters Patent.

Patented Nov. 11, 1919.

Application filed. February 24., 1915.. Serial No. 10,361.

T 0 all whom it may concern:

Be it known that I, OMA CARR, a citizen of the United States of America, and a resident of Asheville, county of Buncombe, State of North Carolina, have invented certain new and useful Improvements in l\/Iethods of and Apparatus for Evaporating Liquids, of which the following is a full and clear specification, reference being bad to the accompanying drawings, in which- Figure 1 is a vertical section of the apparatus showing one possible embodiment of my present invention;

Fig. 2 a sectional view of a preferred form of twin-nozzle atomizing device;

Fig. 3 a vertical sectional view of the apparatus shown in Fig. 1, looking toward the forward end of the apparatus;

Figs. 4 and 5 fragmentary vertical sectional views of the air conduit taken respectively on the lines aa and bb of Fig. 1; and

Figs. 6 and 7 views similar to Figs. 4 and 5 showing a modified form of the conduit.

In the evaporation and desiccation of liquids by floating them in mist in heated air or gas, many devices which have been designed may be applied economically in small capacity, but which fail for various reasons for large capacity. My present invention seeks to supply a method and means whereby very large capacities (hundreds or even thousands of tons daily of dry-powdered product without impractical size of plant) may be realized. In such apparatuses of this type as have been applied industrially, the atomizers or sprayers employed have been limited at most to a few pounds of liquid broken up per hour, while with my method and apparatus I may throw several tons of liquid per atomizer with complete dehydration.

Atomizers of large capacity involve horizontal throw or projection of the spray and mist proportionate to the volume of liquid being sprayed and the pressure employed; and as the practical difference in this respect between small and large capacity atomizers is very great, I will set forth the steps of my invention to show wherein this element is handled in a novel manner:

Take for example the double or twinnozzle atomizer shown in Fig. 2. In this form of atomizer the liquid to be evapothe form of a rated is simultaneously forced through two nozzles a at such angle that the two jets or streams meet each other at a point a short distance in front of the nozzles and are there commingled to form a single stream or jet which is thrown directly forwardly on a line midway between the nozzles. If the nozzles by ths of an inch in diameter and worked under pressure of 1,000 pounds per square inch, they will throw 13.72 tons of liquid (26,440 pounds) per hour. The volocity of the streams at the nozzle will be 380 feet per second, reduced by impact to 250 feet per second, the latter being the horizontal velocity of the spray at instant of release from point of stream impact.

Upon leaving the impact point, the spray begins to diffuse and to lose velocity, at first slowly, then with increasing rate. In still air, this twin atomizer, under 1,000 pounds pressure, will throw horizontally 6.0 feet with moderate diffusion, traversing the gap in a little over one. second. I estimate that at ten feet from the atomizer the velocity will be 150 feet per second, and that the reduction at 10f0ot intervals will be to 53 feet, 25 feet and 14 feet per second, respectively. Without some means for mechanical diffusion of the spray and reduction of velocity, it will be seen that. high capacity atomizers will require very large chambers for natural diffusion and reduction of velocity, and thus not only render plant-cost prohibitive, but also render proper mixture of spray and drying air extremely diificult.

To overcome the above objections, I arrange the atomizer in one wall of a suitable compartment bin such manneras to project the spray horizontally over a slotted or perforated air duct 0, from whlch ]6tS or films of air strike 'the spray and deflect it from its horizontal course, thus creating diffusion and reduced velocity and at the same time giving proper admixture of air and spray. This effect is illustrated approximately by the dotted lines in Figs. 1 and 3. In this manner stop the throw of the atomizer at a distance of 30 feet from the point of atomizing.

Futhermore, because at. any given point in the path of the spray the velocity is differ- -ent from that at any other point and the quantity of passing spray differs likewise,

I construct the air duct 50 that the supply of air will be regulated to suit the conch- I can break up and is proceeding,

tions directly over it at any point. Thus using air at 205210 rahr. and atomizing the weight of air issuing per minute from a point near the nozzle needs to be less than at points farther from the nozzle, because the velocity is greater at that point and less spray will be deflected. in other words, I propose apportioning the weight of the issuing air to the weight of the spray deflected and thus obtain a proper mixture of air and spray at all points along the duct, this being a consideration of great importance in that it not only economizes air, but insures the production of a product having the desired degree of dryness. The final result of this arrangement is that velocity of the spray is broken down and horizontal throw is reduced as to length, while at the same time the whole spray product from large capacity atomizers is thoroughly diffused and properly and proportionately mixed with the heated air.

The liquid to be evaporated may be supplied to the atomizer under pressure in any suitable manner; a simple way is to employ pump (7 and pump the same to an accumulator e, whence it is led by a valved pipe 7* to the atomizer nozzles. The horizontal air duct 0 is supplied by a suitable fan 9 which takes the air from an air heater h.

There are numerous ways of providing for the above described proportionate distribution of air along the length of the spray. In Figs. 6 and 7 I show the conduit as being provided with simple perforations '5, the larger ones being toward the far end of the conduit. For a nicer regulation than can be obtained by a predesigned arrangement of perforations, it will be seen that the perforations may be plugged by means of pins at various points along the conduit to thereby secureany reduction of area desired. In Figs. 4 and 5 I show the conduit, as being provided with longitudinal slits or slots 2" which may, as shown, taper toward the feed end of the conduit and may be provided along the upper surface thereof with longitudinal lips or flanges j capable of being bent toward each other for the purpose of readily varyingthe area of the slots at any point in the length of the conduit.

It will be seen that as the spray is being diffused by the regulable blast, evaporation with uniform absorption by the air at all points on the duct and production of powder of uniform dryness. By

the liquid at the same temperature, very high economy and capacity may be secured, as is obvious. When the spray has been diffused by the blast, I carry the mixture of air and floating particles of dry matter into suitable spaces where velocity reduces and the dry particles drop out. In some cases. simple provision of spaces at the sides of the air conduit, as shown in Fig. 3, is suitable, while in other cases the mixture may be carried into a chamber specifically in tended to reduce current velocity and render the traveling uniform and quiet, as is well known in this art.

Having thus described my invention, what I claim is:

1. An apparatus for evaporating liquids. consisting of a drying chamber, a conduit. extending along the lower'part thereof and. means for supplying the same with a gas under pressure, said conduit being provided along its upper side with openings variable as to area, and means for spraying the liquid to be evaporated along the length of said conduit in the path of the upwardly moving currents of gas issuing therefrom.

:2. An apparatus for evaporating liquids, consisting of a drying chamber. a conduit extending along the lower part thereof and means for supplying the same with a gas under pressure. said conduit being provided along its upper side with openings increasing in area toward the inner end thereof, and means for spraying the liquid to be evaporated along the length of said conduit in the path of the upwardly moving currents of gas issuing therefrom.

3. The method herein described of evaporating liquids, consisting in spraying the liquid into an evaporating chamber m a substantially horizontal direction and in throwing against the spray throughout its length an upwardly moving blast of gas, the volume of the blast increasing toward the far end of the spray, and the blast being of sutlicient strength to carry the solids and vapor upwardly away from the source of the blast for the purpose set forth.

In testimony whereof I hereunto aflix my signature in the presence of two witnesses.

. OMA CAR-R. Witnesses:

A. E. SANDMANN, F. M. NESTLER. 

